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Physics Faculty Publications

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Articles 1 - 30 of 1892

Full-Text Articles in Physical Sciences and Mathematics

Two-Photon Absorption And Fluorescence Of Cadmium Sulfide, Jacob Goranson, Gregory J. Taft Feb 2024

Two-Photon Absorption And Fluorescence Of Cadmium Sulfide, Jacob Goranson, Gregory J. Taft

Physics Faculty Publications

The two-photon absorption and fluorescence of bulk cadmium sulfide were studied using 50-fs, 800-nm pulses from an unamplified Ti:sapphire laser. The fluorescence spectrum was measured to have a main peak at 522 nm, and the power of the fluorescence was shown to vary quadratically with the 800-nm beam power. This supports the theory that the fluorescence is excited by two-photon absorption and confirms previous work done with longer duration, higher energy excitation pulses. Pump-probe measurements provided additional confirmation of the two-photon absorption. Measured spectral broadening of the wings of the laser spectrum also was observed, which likely is due to …

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Magneto-Thermal Limitations In Superconducting Cavities At High Radio-Frequency Fields, I. Parajuli, G. Ciovati, A. Gurevich Jan 2024

Magneto-Thermal Limitations In Superconducting Cavities At High Radio-Frequency Fields, I. Parajuli, G. Ciovati, A. Gurevich

Physics Faculty Publications

The performance of superconducting radio-frequency Nb cavities at high radio-frequency (rf) fields in the absence of field emission can be limited by either a sharp decrease of the quality factor Q0(Bp) above peak surface magnetic fields Bp ∼100 mT or by a quench. We have measured Q0(Bp) at 2 K of several 1.3 GHz single-cell Nb cavities with different grain sizes, and with different ambient magnetic fields and cooldown rates below the critical temperature. Temperature mapping and a novel magnetic field mapping systems were used to find the location of “hot-spots” …

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Counting Linearly Polarized Gluons With Lattice Qcd, Shuai Zhao Jan 2024

Counting Linearly Polarized Gluons With Lattice Qcd, Shuai Zhao

Physics Faculty Publications

We outline an approach to calculate the transverse-momentum-dependent distribution of linearly polarized gluons inside an unpolarized hadron on the lattice with the help of large momentum effective theory. To achieve this purpose, we propose calculating a Euclidean version of the degree of polarization for a fast-moving hadron on the lattice, which is ultraviolet finite, and no soft function subtraction is needed. It indicates a practical way to explore the distribution of the linearly polarized gluons in a proton and the linearly polarized gluon effects in hadron collisions on the lattice.

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Accelerating Markov Chain Monte Carlo Sampling With Diffusion Models, N. T. Hunt-Smith, W. Melnitchouk, F. Ringer, N. Sato, A. W. Thomas, M. J. White Jan 2024

Accelerating Markov Chain Monte Carlo Sampling With Diffusion Models, N. T. Hunt-Smith, W. Melnitchouk, F. Ringer, N. Sato, A. W. Thomas, M. J. White

Physics Faculty Publications

Global fits of physics models require efficient methods for exploring high-dimensional and/or multimodal posterior functions. We introduce a novel method for accelerating Markov Chain Monte Carlo (MCMC) sampling by pairing a Metropolis-Hastings algorithm with a diffusion model that can draw global samples with the aim of approximating the posterior. We briefly review diffusion models in the context of image synthesis before providing a streamlined diffusion model tailored towards low-dimensional data arrays. We then present our adapted Metropolis-Hastings algorithm which combines local proposals with global proposals taken from a diffusion model that is regularly trained on the samples produced during the …

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Beam Spin Asymmetry Measurements Of Deeply Virtual Π⁰ Production With Clas12, The Clas Collaboration, A. Kim, S. Diehl, K. Joo, V. Kubarovsky, P. Achenbach, Z. Akbar, J. S. Alvarado, Whitney R. Armstrong, H. Atac, H. Avakian, C. Ayerbe Gayoso, L. Barion, M. Battaglieri, I. Bedlinskiy, B. Benkel, A. Bianconi, A. S. Biselli, M. Bondi, M. Zureck, Et Al. Jan 2024

Beam Spin Asymmetry Measurements Of Deeply Virtual Π⁰ Production With Clas12, The Clas Collaboration, A. Kim, S. Diehl, K. Joo, V. Kubarovsky, P. Achenbach, Z. Akbar, J. S. Alvarado, Whitney R. Armstrong, H. Atac, H. Avakian, C. Ayerbe Gayoso, L. Barion, M. Battaglieri, I. Bedlinskiy, B. Benkel, A. Bianconi, A. S. Biselli, M. Bondi, M. Zureck, Et Al.

Physics Faculty Publications

The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive π0 production in a wide kinematic region with the photon virtualities Q2 up to 6.6 GeV2and the Bjorken scaling variable 𝓍B in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions. The interpretation of these measurements in terms of the Generalized Parton Distributions …

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A Formalism For Extracting Track Functions From Jet Measurements, Kyle Lee, Ian Moult, Felix Ringer, Wouter J. Waalewijn Jan 2024

A Formalism For Extracting Track Functions From Jet Measurements, Kyle Lee, Ian Moult, Felix Ringer, Wouter J. Waalewijn

Physics Faculty Publications

The continued success of the jet substructure program will require widespread use of tracking information to enable increasingly precise measurements of a broader class of observables. The recent reformulation of jet substructure in terms of energy correlators has simplified the incorporation of universal non-perturbative matrix elements, so called “track functions”, in jet substructure calculations. These advances make it timely to understand how these universal non-perturbative functions can be extracted from hadron collider data, which is complicated by the use jet algorithms. In this paper we introduce a new class of jet functions, which we call (semi-inclusive) track jet functions, which …

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Double Distributions And Pseudodistributions, A. V. Radyushkin Jan 2024

Double Distributions And Pseudodistributions, A. V. Radyushkin

Physics Faculty Publications

We describe the approach to lattice extraction of generalized parton distributions (GPDs) that is based on the use of the double distribution (DD) formalism within the pseudodistribution framework. The advantage of using DDs is that GPDs obtained in this way have the mandatory polynomiality property, a nontrivial correlation between 𝓍 and ξ dependences of GPDs. Another advantage of using DDs is that the D-term appears as an independent entity in the DD formalism rather than a part of GPDs H and E. We relate the ξ dependence of GPDs to the width of the α profiles of the corresponding DDs …

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Definition Of Fragmentation Functions And The Violation Of Sum Rules, John Collins, Ted C. Rogers Jan 2024

Definition Of Fragmentation Functions And The Violation Of Sum Rules, John Collins, Ted C. Rogers

Physics Faculty Publications

We point out a problem with the formulation and derivations of sum rules for quark fragmentation functions that impacts their validity in QCD, but which potentially points toward an improved understanding of final states in inclusive hard processes. Fragmentation functions give the distribution of final-state hadrons arising from a parton exiting a hard scattering, and the sum rules for momentum, electric charge, etc. express conservation of these quantities. The problem arises from a mismatch between the quark quantum numbers of the initial quark and the fact that all observed final-state hadrons are confined bound states with color zero. We point …

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Formulation Of Causality-Preserving Quantum Time Of Arrival Theory, Denny Lane B. Sombillo, Neris I. Sombillo Dec 2023

Formulation Of Causality-Preserving Quantum Time Of Arrival Theory, Denny Lane B. Sombillo, Neris I. Sombillo

Physics Faculty Publications

We revisit the quantum correction to the classical time of arrival to address the unphysical instantaneous arrival in the limit of zero initial momentum. In this study, we show that the vanishing of arrival time is due to the contamination of the causality-violating component of the initial wave packet. Motivated by this observation, we propose to update the temporal collapse mechanism in Galapon (2009) [18] to incorporate the removal of causality-violating spectra of the arrival time operator. We found that the quantum correction to the classical arrival time is still observed. Thus, our analysis validates that the correction is an …

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Exclusive 𝝅⁻ Electroproduction Off The Neutron In Deuterium In The Resonance Region, Y. Tian, R. W. Gothe, V. I. Mokeev, G. Hollis, M. J. Amaryan, W. R. Armstrong, H. Atac, H. Avakian, L. Barion, M. Battaglieri, I. Bedlinskiy, B. Benkel, F. Benmokhtar, A. Bianconi, L. Biondo, A. Biselli, F. Bossù, S. Boiarinov, M. Bondì, J. Zhang, Et Al., The Clas Collaboration Jan 2023

Exclusive 𝝅⁻ Electroproduction Off The Neutron In Deuterium In The Resonance Region, Y. Tian, R. W. Gothe, V. I. Mokeev, G. Hollis, M. J. Amaryan, W. R. Armstrong, H. Atac, H. Avakian, L. Barion, M. Battaglieri, I. Bedlinskiy, B. Benkel, F. Benmokhtar, A. Bianconi, L. Biondo, A. Biselli, F. Bossù, S. Boiarinov, M. Bondì, J. Zhang, Et Al., The Clas Collaboration

Physics Faculty Publications

New results for the exclusive and quasifree cross sections off neutrons bound in deuterium 𝛾vn(p) → pπ− (p) are presented over a wide final state hadron angle range with a kinematic coverage of the invariant mass (W) up to 1.825 GeV and the four-momentum transfer squared (Q2) from 0.4 to 1.0 GeV2. The exclusive structure functions were extracted and their Legendre moments were obtained. Final-state-interaction contributions have been kinematically separated from the extracted quasifree cross sections off bound neutrons solely based on the analysis of the experimental data. These new results will serve as …

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Generation And Characterization Of Magnetized Electron Beam From A Dc High Voltage Photogun For Electron Beam Cooling Application, S.A.K. Wijethunga, M. A. Mamun, R. Suleiman, P. Adderley, B. Bullard, J. Benesch, Jean R. Delayen, J. Grames, C. Hernandez-Garcia, F. Hannon, Geoffrey A. Krafft, G. Palacios-Serrano, M. Poelker, M. Stefani, Y. Wang, S. Zhang Jan 2023

Generation And Characterization Of Magnetized Electron Beam From A Dc High Voltage Photogun For Electron Beam Cooling Application, S.A.K. Wijethunga, M. A. Mamun, R. Suleiman, P. Adderley, B. Bullard, J. Benesch, Jean R. Delayen, J. Grames, C. Hernandez-Garcia, F. Hannon, Geoffrey A. Krafft, G. Palacios-Serrano, M. Poelker, M. Stefani, Y. Wang, S. Zhang

Physics Faculty Publications

One of the most challenging requirements for the proposed Electron–Ion Collider is the strong cooling of the proton beam, which is key to achieving the collider’s desired luminosity of order 1033–1034cm−2s−1. Magnetized bunched-beam electron cooling could be a means to achieve the required high luminosity, where strong cooling is accomplished inside a cooling solenoid where the ions co-propagate with an electron beam generated from a source immersed in a magnetic field. To increase the cooling efficiency, a bunched electron beam with high bunch charge and high repetition rate is required. This work …

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Non-Singlet Quark Helicity Pdfs Of The Nucleon From Pseudo-Distributions, Robert Edwards, Colin Egerer, Joseph Karpie, Nikhil Karthik, Christopher Monahan, Wayne Morris, Kostas Orginos, Anatoly Radyushkin, David Richards, Eloy Romero, Raza Sabbir Sufian, Savvas Zafeiropoulos, On Behalf Of The Hadstruc Collaboration Jan 2023

Non-Singlet Quark Helicity Pdfs Of The Nucleon From Pseudo-Distributions, Robert Edwards, Colin Egerer, Joseph Karpie, Nikhil Karthik, Christopher Monahan, Wayne Morris, Kostas Orginos, Anatoly Radyushkin, David Richards, Eloy Romero, Raza Sabbir Sufian, Savvas Zafeiropoulos, On Behalf Of The Hadstruc Collaboration

Physics Faculty Publications

The non-singlet helicity quark parton distribution functions (PDFs) of the nucleon are determined from lattice QCD, by jointly leveraging pseudo-distributions and the distillation spatial smearing paradigm. A Lorentz decomposition of appropriately isolated space-like matrix elements reveals pseudo-distributions that contain information on the leading-twist helicity PDFs, as well as an invariant amplitude that induces an additional z2 contamination of the leading-twist signal. An analysis of the short-distance behavior of the space-like matrix elements using matching coefficients computed to next-to-leading order (NLO) exposes the desired PDF up to this additional z2 contamination. Due to the non-conservation of the axial current, …

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First Measurement Of Λ Electroproduction Off Nuclei In The Current And Target Fragmentation Regions, T. Chetry, L. El Fassi, W. K. Brooks, R. Dupré, A. El Alaoui, K. Hafidi, P. Achenbach, K. P. Adhikari, Z. Akbar, W.R. Armstrong, M. Arratia, H. Atac, H. Avakian, L. Baashen, N.A. Baltzell, M. Bashkanov, M. Battaglieri, I. Bedlinsky, B. Benkel, M. Zurek, Et Al., Clas Collaboration Jan 2023

First Measurement Of Λ Electroproduction Off Nuclei In The Current And Target Fragmentation Regions, T. Chetry, L. El Fassi, W. K. Brooks, R. Dupré, A. El Alaoui, K. Hafidi, P. Achenbach, K. P. Adhikari, Z. Akbar, W.R. Armstrong, M. Arratia, H. Atac, H. Avakian, L. Baashen, N.A. Baltzell, M. Bashkanov, M. Battaglieri, I. Bedlinsky, B. Benkel, M. Zurek, Et Al., Clas Collaboration

Physics Faculty Publications

We report results of Λ hyperon production in semi-inclusive deep-inelastic scattering off deuterium, carbon, iron, and lead targets obtained with the CLAS detector and the Continuous Electron Beam Accelerator Facility 5.014 GeV electron beam. These results represent the first measurements of the Λ multiplicity ratio and transverse momentum broadening as a function of the energy fraction (z) in the current and target fragmentation regions. The multiplicity ratio exhibits a strong suppression at high zand an enhancement at low z. The measured transverse momentum broadening is an order of magnitude greater than that seen for light mesons. This …

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Neutrino-Tagged Jets At The Electron Ion Collider, Miguel Arratia, Zhong-Bo Kang, Sebouh J. Paul, Alexei Prokudin, Felix Ringer, Fanyi Zhao Jan 2023

Neutrino-Tagged Jets At The Electron Ion Collider, Miguel Arratia, Zhong-Bo Kang, Sebouh J. Paul, Alexei Prokudin, Felix Ringer, Fanyi Zhao

Physics Faculty Publications

We explore the potential of jet observables in charged-current deep inelastic scattering events at the future Electron-Ion Collider. Tagging jets with a recoiling neutrino, which can be identified by the event’s missing transverse momentum, will allow for flavor-sensitive measurements of transverse momentum dependent parton distribution functions. We present the first predictions for transverse-spin asymmetries in azimuthal neutrino-jet correlations and hadron-in-jet measurements. We study the kinematic reach and the precision of these measurements and explore their feasibility using parametrized detector simulations. We conclude that jet production in charged-current deep inelastic scattering, while challenging in terms of luminosity requirements, will complement the …

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Characterization Of Dissipative Regions Of A N-Doped Superconducting Radio-Frequency Cavity, Eric M. Lechner, Basu Dev Oli, Junki Makita, Gianluigi Ciovati, Alex Gurevich, Maria Lavarone Jan 2023

Characterization Of Dissipative Regions Of A N-Doped Superconducting Radio-Frequency Cavity, Eric M. Lechner, Basu Dev Oli, Junki Makita, Gianluigi Ciovati, Alex Gurevich, Maria Lavarone

Physics Faculty Publications

We report radio-frequency measurements of quality factors and temperature mapping of a nitrogen doped Nb superconducting RF cavity. Cavity cutouts of hot and cold spots were studied with low temperature scanning tunneling microscopy and spectroscopy, X-ray photoelectron spectroscopy and secondary electron microscopy. Temperature mapping revealed a substantial reduction of the residual resistance upon cooling the cavity with a greater temperature gradient and hysteretic losses at the quench location, pointing to trapped vortices as the dominant source of residual surface resistance.Analysis of the tunneling spectra in the framework of a proximity effect theory shows that hot spots have a reduced pair …

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Full Treatment Of The Thrust Distribution In Single Inclusive E⁺E⁻ → H X Processes, M. Boglione, Andrea Simonelli Jan 2023

Full Treatment Of The Thrust Distribution In Single Inclusive E⁺E⁻ → H X Processes, M. Boglione, Andrea Simonelli

Physics Faculty Publications

Extending the transverse momentum dependent factorization to thrust dependent observables entails a series of difficulties, ultimately associated to the behavior of soft radiation. As a consequence, the definition of the transverse momentum dependent functions has to be revised, while preserving (and possibly extending) their universality properties. Moreover, the regularization of the rapidity divergences generates non trivial correlations between rapidity and thrust. In this paper, we show how to deal with these correlations in a consistent treatment of the thrust dependence of e+e− → h X cross section, where the hadron transverse momentum is measured with respect to …

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Temperature, Rf Field, And Frequency Dependence Performance Evaluation Of Superconducting Niobium Half-Wave Coaxial Cavity, N. K. Raut, G. Ciovati, S. U. De Silva, J. R. Delayen, P. Dhakal, B. D. Khanal, J. K. Tiskumara Jan 2023

Temperature, Rf Field, And Frequency Dependence Performance Evaluation Of Superconducting Niobium Half-Wave Coaxial Cavity, N. K. Raut, G. Ciovati, S. U. De Silva, J. R. Delayen, P. Dhakal, B. D. Khanal, J. K. Tiskumara

Physics Faculty Publications

Recent advancement in superconducting radio frequency cavity processing techniques, with diffusion of impurities within the RF penetration depth, resulted in high quality factor with increase in quality factor with increasing accelerating gradient. The increase in quality factor is the result of a decrease in the surface resistance as a result of nonmagnetic impurities doping and change in electronic density of states. The fundamental understanding of the dependence of surface resistance on frequency and surface preparation is still an active area of research. Here, we present the result of RF measurements of the TEM modes in a coaxial half-wave niobium cavity …

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Crab Cavities For Ilc, P. A. Mcintosh, S. A. Belomestnykh, G. Burt, R. Calaga, S. U. De Silva, J. R. Delayen, I. V. Gonin, T. N. Khabiboulline, A. Lunin, T. Okugi, Y. M. Orlov, S. Verdú-Andrés, B. P. Xiao, V. P. Yakovlev, A. Yamamoto Jan 2023

Crab Cavities For Ilc, P. A. Mcintosh, S. A. Belomestnykh, G. Burt, R. Calaga, S. U. De Silva, J. R. Delayen, I. V. Gonin, T. N. Khabiboulline, A. Lunin, T. Okugi, Y. M. Orlov, S. Verdú-Andrés, B. P. Xiao, V. P. Yakovlev, A. Yamamoto

Physics Faculty Publications

For the 14 mrad crossing angle proposed, crab cavity systems are fundamentally anticipated for the viable operation of the International Linear Collider (ILC), in order to maximise its luminosity performance. Since 2021, a specialist development team have been defining optimum crab cavity technologies which can fulfil the operational requirements for ILC, both for its baseline centre-of-mass energy of 250 GeV, but also extending those requirements out to higher beam collision intensities. Five design teams have established crab cavity technology solutions, which have the capability to also operate up to 1 TeV centre-of-mass. This presentation showcases the key performance capabilities of …

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Electron Scattering And Neutrino Physics, A. M. Ankowski, A. Ashkenazi, S. Bacca, J. L. Barrow, M. Betancourt, A. Bodek, M. E. Christy, L. Doria, S. Dytman, A. Friedland, O. Hen, C. J. Horowitz, N. Jachowicz, W. Ketchum, T. Lux, K. Mahn, C. Mariani, J. Newby, V. Pandey, A. Papadopoulou, E. Radicioni, F. Sánchez, C. Sfienti, J. M. Udías, L. Weinstein, L. Alvarez-Ruso, J. E. Amaro, C. A. Argüelles, A. B. Balantekin, S. Bolognesi, V. Brdar, P. Butti, S. Carey, Z. Djurcic, O. Dvornikov, S. Edayath, S. Gardiner, J. Isaacson, W. Jay, K. S. Mcfarland, A. Nikolakopoulos, A. Norrick, S. Pastore, G. Paz, M. H. Reno, I. Ruiz Simo, J. E. Sobczyk, A. Sousa, N. Toro, Y. D. Tsai, M. Wagman, J. G. Walsh, G. Yang Jan 2023

Electron Scattering And Neutrino Physics, A. M. Ankowski, A. Ashkenazi, S. Bacca, J. L. Barrow, M. Betancourt, A. Bodek, M. E. Christy, L. Doria, S. Dytman, A. Friedland, O. Hen, C. J. Horowitz, N. Jachowicz, W. Ketchum, T. Lux, K. Mahn, C. Mariani, J. Newby, V. Pandey, A. Papadopoulou, E. Radicioni, F. Sánchez, C. Sfienti, J. M. Udías, L. Weinstein, L. Alvarez-Ruso, J. E. Amaro, C. A. Argüelles, A. B. Balantekin, S. Bolognesi, V. Brdar, P. Butti, S. Carey, Z. Djurcic, O. Dvornikov, S. Edayath, S. Gardiner, J. Isaacson, W. Jay, K. S. Mcfarland, A. Nikolakopoulos, A. Norrick, S. Pastore, G. Paz, M. H. Reno, I. Ruiz Simo, J. E. Sobczyk, A. Sousa, N. Toro, Y. D. Tsai, M. Wagman, J. G. Walsh, G. Yang

Physics Faculty Publications

A thorough understanding of neutrino–nucleus scattering physics is crucial for the successful execution of the entire US neutrino physics program. Neutrino–nucleus interaction constitutes one of the biggest systematic uncertainties in neutrino experiments—both at intermediate energies affecting long-baseline deep underground neutrino experiment, as well as at low energies affecting coherent scattering neutrino program—and could well be the difference between achieving or missing discovery level precision. To this end, electron–nucleus scattering experiments provide vital information to test, assess and validate different nuclear models and event generators intended to test, assess and validate different nuclear models and event generators intended to be used …

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Observation Of Correlations Between Spin And Transverse Momenta In Back-To-Back Dihadron Production At Clas12, H. Avakian, T.B. Hayward, A. Kotzinian, W.R. Armstrong, H. Atac, C. Ayerbe Gayoso, L. Baashen, N.A. Balzell, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, B. Benkel, F. Benmokhtar, A. Bianconi, L. Biondo, A. S. Biselli, M. Bondi, S. Boiarinov, M. Zurek, Et Al. Jan 2023

Observation Of Correlations Between Spin And Transverse Momenta In Back-To-Back Dihadron Production At Clas12, H. Avakian, T.B. Hayward, A. Kotzinian, W.R. Armstrong, H. Atac, C. Ayerbe Gayoso, L. Baashen, N.A. Balzell, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinskiy, B. Benkel, F. Benmokhtar, A. Bianconi, L. Biondo, A. S. Biselli, M. Bondi, S. Boiarinov, M. Zurek, Et Al.

Physics Faculty Publications

We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction in the deep inelastic scattering process. In this reaction, two hadrons are produced in opposite hemispheres along the z axis in the virtual photon-target nucleon center-of-mass frame, with the first hadron produced in the current-fragmentation region and the second in the target-fragmentation region. The data were taken with longitudinally polarized electron beams of 10.2 and 10.6 GeV incident on an unpolarized liquid-hydrogen target using the CLAS12 spectrometer at Jefferson Lab. Observed nonzero sinΔϕ modulations in ep→e'pπ+ X events, where Δϕ is the difference …

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A Multidimensional Study Of The Structure Function Ratio Σlt'/ Σ₀ From Hard Exclusive ��⁺ Electro-Production Off Protons In The Gpd Regime, S. Diehl, A. Kim, K. Joo, P. Achenbach, Z. Akbar, M. J. Amaryan, H. Atac, H. Avagyan, C. Ayerbe Gayoso, L. Baashen, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinsky, B. Benkel, F. Benmokhtar, A. Bianconi, A. S. Biselli, M. Bondi, W.A. Booth, M. Zurek, Et Al. Jan 2023

A Multidimensional Study Of The Structure Function Ratio Σlt'/ Σ₀ From Hard Exclusive ��⁺ Electro-Production Off Protons In The Gpd Regime, S. Diehl, A. Kim, K. Joo, P. Achenbach, Z. Akbar, M. J. Amaryan, H. Atac, H. Avagyan, C. Ayerbe Gayoso, L. Baashen, L. Barion, M. Bashkanov, M. Battaglieri, I. Bedlinsky, B. Benkel, F. Benmokhtar, A. Bianconi, A. S. Biselli, M. Bondi, W.A. Booth, M. Zurek, Et Al.

Physics Faculty Publications

A multidimensional extraction of the structure function ratio from the hard exclusive →ep → e'n��+ reaction above the resonance region has been performed. The study was done based on beam-spin asymmetry measurements using a 10.6 GeV incident electron beam on a liquid-hydrogen target and the CLAS12 spectrometer at Jefferson Lab. The measurements focus on the very forward regime (t/Q2≪ 1) with a wide kinematic range of in the valence regime (0.17 < ��B < 0.55), and virtualities ranging from 1.5 GeV2 up to 6 GeV2. The results and their comparison to theoretical models based on Generalized Parton Distributions demonstrate the sensitivity to chiral-odd …

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Scattered Spectra From Inverse Compton Sources Operating At High Laser Fields And High Electron Energies, Geoffrey A. Krafft, Balša Terzić, Erik Johnson, G. Wilson Jan 2023

Scattered Spectra From Inverse Compton Sources Operating At High Laser Fields And High Electron Energies, Geoffrey A. Krafft, Balša Terzić, Erik Johnson, G. Wilson

Physics Faculty Publications

As Compton x-ray and gamma-ray sources become more prevalent, to understand their performance in a precise way, it becomes important to be able to compute the distribution of scattered photons precisely. For example, codes have been developed at Old Dominion University which were used to understand the performance of the Dresden Compton Source in detail. An ideal model would (i) include the full Compton effect frequency relations between incident and scattered photons, (ii) allow the field strength to be large enough that nonlinear effects are captured, and (iii) allow the effects of electron beam emittance to be introduced and studied. …

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Cavity And Cryomodule Developments For Eic, R. A. Rimmer, E. Daly, J. Guo, J. Henry, J. Matalevich, H. Wang, S. Wang, D. Holmes, K. Smith, W. Xu, A. Zaltsman, B. Xiao, Subashini De Silva, Jean R. Delayen Jan 2023

Cavity And Cryomodule Developments For Eic, R. A. Rimmer, E. Daly, J. Guo, J. Henry, J. Matalevich, H. Wang, S. Wang, D. Holmes, K. Smith, W. Xu, A. Zaltsman, B. Xiao, Subashini De Silva, Jean R. Delayen

Physics Faculty Publications

The EIC is a major new project under construction at BNL in partnership with JLab. It relies upon a number of new SRF cavities at 197 MHz, 394 MHz, 591 MHz and 1773 MHz to pre-bunch, accelerate, cool and crab the stored beams. R&D is focusing on the 591 MHz elliptical cavity and 197 MHz crab cavity first as these are the most challenging. Preliminary designs of these cavities are presented along with an R&D status report. To avoid developing multiple different cryostats a modular approach is adopted using a high degree of commonality of parts and systems. This approach …

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Resolution To The Problem Of Consistent Large Transverse Momentum In Tmds, J. O. Gonzalez-Hernandez, Tommaso Rainaldi, Ted Rogers Jan 2023

Resolution To The Problem Of Consistent Large Transverse Momentum In Tmds, J. O. Gonzalez-Hernandez, Tommaso Rainaldi, Ted Rogers

Physics Faculty Publications

Parametrizing TMD parton densities and fragmentation functions in ways that consistently match their large transverse-momentum behavior in standard collinear factorization has remained notoriously difficult. We show how the problem is solved in a recently introduced set of steps for combining perturbative and nonperturbative transverse momentum in TMD factorization. Called a “bottom-up” approach in a previous article, here we call it a “hadron structure oriented” (HSO) approach to emphasize its focus on preserving a connection to the TMD parton model interpretation. We show that the associated consistency constraints improve considerably the agreement between parametrizations of TMD functions and their large-kT behavior, …

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Machine-Assisted Discovery Of Integrable Symplectic Mappings, T. Zolkin, Y. Kharkov, S. Nagaitsev Jan 2023

Machine-Assisted Discovery Of Integrable Symplectic Mappings, T. Zolkin, Y. Kharkov, S. Nagaitsev

Physics Faculty Publications

We present a new automated method for finding integrable symplectic maps of the plane. These dynamical systems possess a hidden symmetry associated with an existence of conserved quantities, i.e., integrals of motion. The core idea of the algorithm is based on the knowledge that the evolution of an integrable system in the phase space is restricted to a lower-dimensional submanifold. Limiting ourselves to polygon invariants of motion, we analyze the shape of individual trajectories thus successfully distinguishing integrable motion from chaotic cases. For example, our method rediscovers some of the famous McMillan-Suris integrable mappings and ultradiscrete Painlevé equations. In total, …

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Searching For Prompt And Long-Lived Dark Photons In Electroproduced E⁺ E⁻ Pairs With The Heavy Photon Search Experiment At Jlab, P. H. Adrian, N. A. Baltzell, M. Battaglieri, M. Bondí, S. Boyarinov, S. Bueltmann, P. Butti, V. D. Burkert, D. Calvo, T. Cao, M. Carpinelli, A. Celentano, G. Charles, L. Colaneri, W. Cooper, D. Crowe, C. Cuevas, A. D'Angelo, N. Dashyan, B. Wojtsekhowski, Et Al. Jan 2023

Searching For Prompt And Long-Lived Dark Photons In Electroproduced E⁺ E⁻ Pairs With The Heavy Photon Search Experiment At Jlab, P. H. Adrian, N. A. Baltzell, M. Battaglieri, M. Bondí, S. Boyarinov, S. Bueltmann, P. Butti, V. D. Burkert, D. Calvo, T. Cao, M. Carpinelli, A. Celentano, G. Charles, L. Colaneri, W. Cooper, D. Crowe, C. Cuevas, A. D'Angelo, N. Dashyan, B. Wojtsekhowski, Et Al.

Physics Faculty Publications

The heavy photon search experiment (HPS) at the Thomas Jefferson National Accelerator Facility searches for electroproduced dark photons. We report results from the 2016 engineering run consisting of 10 608  nb−1 of data for both the prompt and displaced vertex searches. A search for a prompt resonance in the e+e− invariant mass distribution between 39 and 179 MeV showed no evidence of dark photons above the large QED background, limiting the coupling of ε2≳10−5, in agreement with previous searches. The search for displaced vertices showed no evidence of excess signal over background …

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The Post-Shock Nonequilibrium Relaxation In A Hypersonic Plasma Flow Involving Reflection Off A Thermal Discontinuity, Anna Markhotok Jan 2023

The Post-Shock Nonequilibrium Relaxation In A Hypersonic Plasma Flow Involving Reflection Off A Thermal Discontinuity, Anna Markhotok

Physics Faculty Publications

The evolution in the post shock nonequilibrium relaxation in a hypersonic plasma flow was investigated during a shock’s reflection off a thermal discontinuity. Within a transitional period, the relaxation zone parameters past both, the reflected and transmitted waves, evolve differently compared to that in the incident wave. In a numerical example for the non-dissociating N2 gas heated to 5000 K/10,000 K across the interface and M = 3.5, the relaxation time for the transmitted wave is up to 50% shorter and the relaxation depth for both waves is significantly reduced, thus resulting in a weakened wave structure. The …

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Quantum Efficiency Enhancement In Simulated Nanostructured Negative Electron Affinity Gaas Photocathodes, Md Aziz Ar Rahman, Shukui Zhang, Hani E. Elsayed-Ali Jan 2023

Quantum Efficiency Enhancement In Simulated Nanostructured Negative Electron Affinity Gaas Photocathodes, Md Aziz Ar Rahman, Shukui Zhang, Hani E. Elsayed-Ali

Physics Faculty Publications

Nanostructured negative electron affinity GaAs photocathodes for a polarized electron source are studied using finite difference time domain optical simulation. The structures studied are nanosquare columns, truncated nanocones, and truncated nanopyramids. Mie-type resonances in the 700–800 nm waveband, suitable for generation of polarized electrons, are identified. At resonance wavelengths, the nanostructures can absorb up to 99% of the incident light. For nanosquare columns and truncated nanocones, the maximum quantum efficiency (QE) at 780 nm obtained from simulation is 27%, whereas for simulated nanopyramids, the QE is ∼21%. The high photocathode quantum efficiency is due to the shift of Mie resonance …

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Prospects For 𝛾*𝛾* → 𝜋𝜋 Via Lattice Qcd, Raúl Briceño, Andrew W. Jackura, Arkaitz Rodas, Juan V. Guerrero Jan 2023

Prospects For 𝛾*𝛾* → 𝜋𝜋 Via Lattice Qcd, Raúl Briceño, Andrew W. Jackura, Arkaitz Rodas, Juan V. Guerrero

Physics Faculty Publications

The 𝛾*𝛾* → 𝜋𝜋 scattering amplitude plays a key role in a wide range of phenomena, including understanding the inner structure of scalar resonances as well as constraining the hadronic contributions to the anomalous magnetic moment of the muon. In this work, we explain how the infinite-volume Minkowski amplitude can be constrained from finite-volume Euclidean correlation functions. The relationship between the finite-volume Euclidean correlation functions and the desired amplitude holds up to energies where 3𝜋 states can go on shell, and is exact up to exponentially small corrections that scale like 𝒪(e−m𝜋L), where L is the spatial extent …

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Machine Learning-Based Jet And Event Classification At The Electron-Ion Collider With Applications To Hadron Structure And Spin Physics, Kyle Lee, James Mulligan, Mateusz Płoskoń, Felix Ringer, Feng Yuan Jan 2023

Machine Learning-Based Jet And Event Classification At The Electron-Ion Collider With Applications To Hadron Structure And Spin Physics, Kyle Lee, James Mulligan, Mateusz Płoskoń, Felix Ringer, Feng Yuan

Physics Faculty Publications

We explore machine learning-based jet and event identification at the future Electron-Ion Collider (EIC). We study the effectiveness of machine learning-based classifiers at relatively low EIC energies, focusing on (i) identifying the flavor of the jet and (ii) identifying the underlying hard process of the event. We propose applications of our machine learning-based jet identification in the key research areas at the future EIC and current Relativistic Heavy Ion Collider program, including enhancing constraints on (transverse momentum dependent) parton distribution functions, improving experimental access to transverse spin asymmetries, studying photon structure, and quantifying the modification of hadrons and jets in …

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